I dropped my tranny out to put in a stall converter last week and my alternator stopped charging. I changed out alternators and it made no difference. I dont have any current on the wire that plugs into the alternator that should have power when the key is on. I saw in alldata that the wireing for the alternator ties into the tranny wiring somewhere and was hoping someone out there could tell me where to look.

The car is an 87 Z28 700r4. I dropped the trnny out far enough to pull the torque converter out and swap in the higher stall. I dissconected the TV cable from up top, the speedo cable, one wire plug, shift linakge, and the oil cooler lines from radiator. When I dropped the tranny I pulled some wire connection loose, any help would be great.

 

(As far as I know) if the alternator is spinning, its putting power out on that large wire coming from the back. If its connected to the battery then you *should* be charging. Check for clean connections around the alternator and battery terminals?

 

The alternator is good. The 3 wire connector that plugs into the back is the problem. One of the wires should have power at all times (it does) another wire should have power when the key is turned to the On position (it doesn't) For some reason the alternator wiring runs in with the tranny wiring, thats the connection I am trying to find. I know how stupid it sounds.

 

Well according to the schematics from the Helms service manual, the red wire to the alternators 3 wire connector is always hot because it is a fusible link to the starter solenoid. The tan/white wire is hot in run and goes to the fan fuse and coolant fan relay. The brown wire is also hot in run and goes to the gages fuse and voltage indicator on the cluster. These three wires are for the built in voltage regulator on the alternator. There are also only three wires for the tranny on your car and they all go into that one plug on the left side of the tranny case for the TCC solenoid and 4th gear switch. You do not have a switch there for the back-up light since yours is an automatic. You might have pulled the wire connection loose for the heavy duty coolant fan switch located on the right side of the engine block above the starter and this is tied into the coolant fan relay and is part of the charging circuit.